Muscles in the living body, usually for purposes of muscle growth, are subjected in fitness studios or with personal trainers for example to electric stimuli by electric muscle stimulation (EMS), which is also partly known as electromyostimulation, in order to strengthen the muscles.
Conventional EMS electrodes to be applied to the body frequently include textile structures with incorporated metal filaments, especially silver or copper metal filaments, or pads such as polymer pads which are filled with conductive particles (e.g. carbon black). An EMS electrode is disclosed for example in the German patent application DE 10 2007 046 886 A1.
Such EMS electrodes are usually wetted before training or carried over a wetted underwear garment such as a T-shirt for example, for which purpose they are usually attached to an electrode carrier, which can be applied to the body. Whereas earlier electrode carriers frequently consisted of belt strips and leather strips, on which the electrodes were attached, the development is increasingly moving towards EMS garments, especially textile garments which carry the electrodes and can be carried by the training person themselves like a garment, i.e. as a vest, pant, stocking, armband or the like. In order to further increase the acceptance of the electric muscle stimulation (EMS), efforts are made to integrate the electrodes and the strip conductors connected to the electrodes in an increasingly better way into the EMS garment in order to thus eliminate the visible cables or at least shorten the cables leading from the EMS garment to an external control unit, and to not only eliminate the visibility of the electrodes to the greatest possible extent, but also to generally increase the wearing comfort of the EMS garment in that the EMS electrodes are formed in the most flexible and extensible manner, frequently made of textile materials. One example for such an EMS garment is disclosed in the German patent DE 10 2009 017 179 B4.
Currently, accumulator-driven EMS stimulus generation units exist, which form the EMS stimuli to be delivered to the body via the EMS electrodes and therefore can be carried directly on the EMS garment and thus on the body in an “autonomous” manner, see U.S. Pat. No. 9,067,199 and U.S. Patent Application Publication No. 2015/0202429. However, the battery power is usually insufficient in order to generate said EMS stimuli, which consist of current pulses and/or alternating current, beyond a period of time which is acceptable in training operation. For the purpose of generating said EMS stimuli, the EMS stimulus generating device usually includes an electric pulse generator for generating said EMS stimuli, as well as an electronic controller which predetermines a stimulation diagram, on the basis of which a plurality of EMS stimuli, which are distributed in respect of time and among the EMS electrodes of the EMS training device, are formed from a current drawn from a current source, which EMS stimuli consist of the current pulses and/or alternating current with values such as amplitude and frequency, which are predetermined by the controller, and with which the EMS electrodes are supplied in order to conduct a current through the body with a predetermined amplitude and frequency pattern. In this process, the EMS electrodes are usually grouped on the EMS garment in pairs, so that two EMS electrodes that are grouped to form such a pair are each connected via a line branch to the EMS stimulus generating unit, which are completed into a closed current circuit through the body on which they rest during EMS training, which current circuit leads through the body and thus through the muscles.
The line branches connecting the EMS electrodes to the EMS stimulus generating unit are formed as EMS signal cables at least between a connecting point on the EMS garment and the EMS stimulus generating unit, which EMS signal cables usually lead from the EMS stimulus generating unit, which is usually arranged remote from the training person and thus from the worn EMS garment, to the EMS electrodes or to respective connections on the EMS garment or garments. The EMS stimulus generating unit is usually housed in a control unit having a user interface, frequently in form of a control panel, and connected to the regular power grid. Such EMS training devices are produced by numerous producers and operated professionally in fitness studios by personal trainers etc., but also by private persons directly. The EMS electrodes are interconnected to the EMS stimulus generating unit, i.e. a control device, which operates for example in a frequency range of 2 to 150 Hz with a pulse width of 50 to 400 μs and an interpulse period of 0 to 10 seconds. The maximum peak value of the electrical output voltage lies at 70 to 160 V at a current intensity of approximately 10 to 20 mA, for example.
While the successes of the EMS method in muscle growth is undisputed and EMS training devices are gaining increasing interest in the audience as a result of the increasingly improved outer appearance, systematic problems are becoming more apparent due to the higher use. Consequently, inexplicable and randomly occurring failures of EMS electrodes occur in use, which leads in current EMS garments, in which the electrodes are already integrated, to the exchange of the entire EMS garment, i.e. training suit sweaters. A failure of an electrode means in this context that the EMS electrode in question no longer supplies any pulse current to the body or only an inadequate pulse current, even though no power line or contact point between the EMS electrode and the EMS stimulus generating unit, which supplies the electrode with current, seems to be broken and no defect is externally visible on the electrode.